Mr. Ajami is a senior fellow at Stanford's Hoover Institution and the author, most recently, of "The Syrian Rebellion" (Hoover Press, 2012).Nowadays, few people step forth to speak well of the Iraq War, to own up to the support they gave that American campaign in the Arab world. Yet Operation Iraqi Freedom, launched 10 years ago this week, was once a popular war. We had struck into Afghanistan in 2001 to rout al Qaeda and the terrorists' Taliban hosts—but the 9/11 killers who brought ruin onto American soil were not Afghan. They were young Arabs, forged in the crucible of Arab society, in the dictators' prisons and torture chambers. Arab financiers and preachers gave them the means and the warrant for their horrific deeds.America's previous venture into Iraq, a dozen years earlier, had been a lightning strike: The Iraqi dictator was evicted from Kuwait and then spared. Saddam Hussein's military machine was all rust and decay by 2003, but he swaggered and let the world believe that he had in his possession a deadly arsenal of weapons of mass destruction. The Arab redeemer, as he had styled himself, lacked the guile that might have saved him. A great military expedition was being readied against him in London and Washington, but he gambled to the bitter end that George W. Bush would not pull the trigger....